Objective:

To determine if the L3-4 disc angle may be a surrogate marker for global lumbar alignment in thoracolumbar fusion surgery. To explore the relationship between radiographic and patient-reported outcomes (PROs) after thoracolumbar fusion surgery.

Methods:

Retrospective chart review was conducted on patients who had undergone a lumbar fusion involving levels from T9 to pelvis. EuroQol-Five Dimension (EQ-5D) scores and adverse events including adjacent segment disease and degeneration, pseudoarthrosis, proximal junctional kyphosis, stenosis, and reoperation were collected. Pre- and postoperative spinopelvic parameters were measured on weight-bearing radiographs, with the L3-4 disc angle of novel interest. Univariate logistic and linear regression were performed to assess the associations of radiographic parameters with adverse event incidence and improvement in EQ-5D, respectively.

Results:

182 patients met inclusion criteria. Univariable analysis revealed that increased magnitude of L3-4 disc angle, anterior pelvic tilt, and pelvic incidence measures are associated with increased likelihood of developing postoperative adverse events. Conversely, increased lumbar lordosis demonstrated a decreased incidence of developing a postoperative adverse event. Linear regression showed that radiographic parameters did not significantly correlate with postoperative EQ-5D scores although scores were significantly improved post-fusion in all dimensions except Self-care (P = 0.51).

Conclusions:

L3-4 disc angle magnitude may serve as a surrogate marker of global lumbar alignment. Degree of spinopelvic alignment did not correlate to improvement in EQ-5D score in the present study, suggesting that quality of life metric change may not be a sensitive or specific marker of post-fusion alignment.